(1) Field of the Invention
The present invention relates to an automatic white-balance adjusting apparatus for automatically carrying out a white-balance adjustment operation needed for correctly reproducing colors in a video camera, an electronic still camera or the like depending on a color temperature of a light source, and more particularly to an improved automatic white-balance adjusting apparatus of the above-noted type comprising light measuring means for generating a light measurement signal by receiving light from a light source, determining means for calculating and determining color temperature adjustment data for a white-balance adjustment operation from color temperature information of the light source obtained from the light measurement signal from the light measurement means and adjusting means for adjusting a white-balance based on the color temperature adjustment data.
(2) Description of the Prior Art
A white-balance adjustment operation by a conventional white-balance adjusting apparatus is carried out by using color temperature information obtained by color temperature sensors each time a switch attached to a video camera or the like is depressed or at every predetermined time interval.
However, according to the above construction, even if a momentary change in the light illuminating an object to be photographed unexpectedly occurs, or light reflected from another object having a high brightness value is momentarily incident onto the sensors, a white-balance adjustment signal is generated based on a color temperature measured at that particular moment. Therefore, since the white-balance adjustment signal varies even with a momentary change in the color temperature, instability or inaccuracy in the color reproduction occurs.
In view of the above-noted state of the art, it is a primary object of the present invention to provide an automatic white-balance adjusting apparatus capable of achieving stable and accurate color reproduction. In accordance with the invention, the white-balance adjustment condition does not change significantly even if a violent and sudden change occurs during the light in the course of an image recording operation using a video camera, an electronic still camera or the like.
It is another object of the present invention to provide an automatic white-balance adjusting apparatus capable of maintaining the white-balance adjustment condition constant in case such a sudden change in the light disappears at once.